OBJECTIVES: a. To characterize more precisely the abnormalities of identification and localization of visual patterns in patients with cerebral lesions involving occipital, parietal, and temporal lobes. b. Through such characterization to distinguish according to anatomic site of lesion, different patterns of abnormal behavior with visual stimuli. c. By so correlating behavioral abnormalities with lesion site to evolve a theory of how the pattern of anatomic connections in the occipital, parietal, and temporal lobes guarantees the normal capacities for identification and localization of visual patterns. Goals this year are to continue our detection and study of patients with disordered visual identification and localization; to concentrate especially on the mechanism underlying the inability to identify faces (prosopagnosia) in some of these patients.